Processes for alkylating a variety of alkylatable aromatic compounds by contacting such compounds with a hydrocarbon radical providing source such as an olefin or alcohol are widely known. Typically, alkylatable aromatic compounds are mononuclear aromatic compouns themselves or those substituted with a hydroxyl, amine or an ether group. The alkylation has been carried out in the prsence of homogeneous and heterogeneous catalyst systems.
Ring alkylated aromatic amines have been some of the products produced by alkylation procedures. Ring alkylated aromatic amines have a variety of used in chemical synthesis. Some of the early uses were intermediates for substituted isocyanates, herbicidal compositions, dyestuffs and textile auxiliary agents. More recently aromatic amines have been utilized as chain lengthening or cross-linking components in polyurethane systems. These are commonly referred to as chaine xtenders.
Representative references which illustrate some of the early processes in forming ring alkylated aromati amines are:
British Pat. No. 414,574 discloses the reaction of aniline with various olefins, e.g., cyclohexene and alcohols,e .g., butanol in the presence of a neutral or weakly acidic catalyst system commonly referred to as hydrosilicates at tempeatures from 200.degree.-270.degree. C. Ortho and paracyclohexylaniline, N-cyclohexylaniline, N0butylaniline and para-methylortho-cyclohexylaniline and N-cyclohexy-para-toluidine are listed as representative products.
AS No. 1,051,271 discloses the ring alkylation of aniline with an olefin, e.g., ethylene, in the presence of akaolin or in the presence of aluminum and aluminum alloys. Alkylation with higher olefins, e.g., propylene, butlene, etc., was carried out in the presence of Friedel-Crafts catalyst or bleaching earths under liquid phase conditions at temperatures from 150.degree.-350.degree. C. Examples of catlytic systems included aluminum chloride, ainz chloride, boron trifluoride, sulfuric acid, phosphoric acid and bleaching earth. Ring alkylation at the ortho-position was predominant, although other products such as the di and tri-alkylated aniline product were produced.
In an article by Zollner and Marton, Acta Chim. Hung. TOmus 20, 1959 (Pages 321-329) the vapor phase alkylation of aniline with ethanol was effected in the presence of aluminum oxide.
U.S. Pat. Nos. 3,649,693 and 3,923,892 discloses the preparation of ring alkylated aromatic amines by reacting an aromatic amine with an olefin in the presence of aluminum anilide, optionally including a Friedel-Crafts promoter. Reaction products include 2-ethylaniline, and 2,6-diethylaniline.
Stroh, et al., in U.S. Pat. Nos. 3,275,690; 2,762,845, Japanese Sho No. 56-110652, and, as mentioned previously, AS No. 1,051,271, disclose various processes for preparing alkylated aromatic amines by reacting an aromatic amine with an olefin in the presence of Friedel-Crafts catalysts as well as a combination of Friedel-Crafts catalysts in teh prsence of halogen compounds combined with aluminum. Representative reaction products included 2-cyclohexylaniline, diethyltoluenediamine, diethylaniline, diisopropylaniline and mono-tert-butylaniline.
The art, e.g., Netherlands Application No. 6,407,636 has recognized that alkylation of various aromatic and heterocyclic compounds can be carried out in the presence of an zeolite having a pore size from 6-15 Angstroms wherein active cationic sites are obtained with an exchangeable metal or hydrogen cations in their ordered internal structure. Alkylating agents include olefins having from 2 to 12 carbon atoms, alkyl halides such as propylbromide and nethylchloride; and alcohols, such as, methanol, ethanol, and propanol. Various compounds were suggested as being suited for alkylation and these include both the heterocyclic and aromatic ring compounds. For aromatic amine alkylatio it was suggested that a zeolite with a sparse distribution of acidic sites should be utilized. It was believed the highly acidic zeolite catalysts which have a high density of acidic sites may bind the amine to the catalyst and block the pore structures. In Example 1 aniline was alkylated with propylene using sodium zeolite X having a pore size of 8 Angstroms and numerous alkylated amines were produced. Example 3 shows alkylation of diphenylamine with cyclohexene using a rare earth exchanged X zeolite. Again, numerous ring alkylated products were produced and high temperatures, e.g. 300.degree. C. and above apparently being required to weaken the amine-acid bond.
French Pat. No. 1,406,73, which is equivalent to Netherlands Application No. 6,407,636, discloses the preparation of alkylated aromatic compounds having polar substitutionsn thereon utilizing alumino-silicates having a pore size of at least 6 Angstroms as a catalyst. Cations of low valence were deemed to have been particularly effective for the ring alkylation of aromatic compounds having weakly basic substituents such as aromatic amines. The examples show the alkylation of aniline with propylene in the presence of a sodium zeolite X and alkylation of diphenylamine with propylene in the presence of a molecular sieve 13X which has undergone a partial exchange with rare earths and having a pore size of 8 .ANG..
U.S. Pat. No. 3,201,486 discloses prior art processes for alkylating various aromatic hydrocarbons with an olefin using sulfuric acid andn hydrogen fluoride as a catalyst. In the particular reference solid phosphooric acid was used as the catlyst.
U.S. Pat. Nos. 3,178,365; 3,281,483; 4,2559,537; 4,395,372 and 4,393,262 disclose the alkylation of aromatic hydrocarbon compounds with an olefin in the presence of various crystalline alumino-silicates, such as crystalline alumino-silicates having undergone previous transformation by reaction with a nitrogen oxide containing compound, a hydrogen mordenite, a ZSM catalyst exchanged with a Group VIa metal; crystalline alumino-silicates promotd with sulfur dioxide and dealuminated zeolites. The dealuminated, high silica zeolites are preferred as having particular activity for the alkylation of benzene.
Although the prior art has disclosed that a variety of catlytic systems cna be utilized in the alkylation of aromatic hydrocarbons and aromatic amines, teh art also teaches that a variety of reactin products are produced, including both ortho and para-isomers of mononuclear aromatic amines as well as, mono, di and tri alkyl substituted amines. In addition the prior art teaches that neutral to weakly acidic catalysts are preferred for effectign ring alkylation of the aromatic amines. Even though the prior art has suggested preferred catalytic systems such systems also involve batch, liquid phase opeation which may be difficult to operate over an extended period of time, and tend to give more para product. In addition, many of the processes suffer from poor conversion, poor reaction rate and an inability to produce high ortho to para isomer ratios at high conversion.
U.S. Pat. No. 4,224,188 describes the preparation of Al exchanged zeolites for the cracking of petroleum feeds. The catalysts are prepared by ion exchange of NH.sub.4 Y or NaY with solutions of al(N.sub.3).sub.3 at pH=3.2-3.25. The techniques described in this patent suggest that the preferred method of preparing these materials is to first Al exchange NaY then NH.sub.4 exchange the resulting AlNaY zeolite.
K. M. Wang and J. H. Lunsford, J. Catalysis, 24, 62, 1972, report the preparation and catalytic properties of Al exchanged zeolites for the disproportionation of toluene. The zeolites were prepared by contacting NaY zeolite with a solution of 1M Al(N.sub.3).sub.3 for 1-142 hours. The zeolites prepared in this manner where shown to be more active than HY, prepared from NH.sub.4 Y for toluene disproportionation. This initial activity was lost however, and the catalyst resulted in the same activity as HY. It was also reported that there was no correlation to the number of Al cations exchange dinto teh zeolite and the catalyst activity.
B. Wichterlova, et all. in the Proceeding of the Fifth International Zeolite Conference also described the Al exchanged zeolites and compared them to dehydroxylated and steamed zeolites for ethylene oligomerization. It was reported that zeolites prepared in this manner were more active for ethylene oligomerization than were HY zeolites prepared by NH.sub.4 exchange of Y zeolites.